Cover crops: long-term benefit

LOCKEFORD — Farmers and ranchers primarily focus on growing plants that produce food or fiber — something of value they can sell and get cash to pay their bills for seed, farm labor, fuel and fertilizer and, hopefully, keep something for themselves.

But researchers at the Lockeford Plant Materials Center are encouraging growers to think differently — to cultivate cover crops, noncommercial plants that can improve the soil and more.

“They have so many benefits,” said Margaret Smither-Kopperl, manager of the U.S. Department of Agriculture research facility. “What we’re trying to do here is useful for all of us.”

Cover crops can help break up soil, improving water infiltration. and add organic material, which boosts the soil’s ability to retain water. They also can inhibit weed growth, provide nutrients for commercial crops and sustain beneficial insects.

During a field day attended by about two dozen farmers at the center last week, Smither-Kopperl acknowledged that water use by cover crops is a concern, especially with California entering a fourth year of drought.

But by helping soil retain moisture, she said, “They can actually store water in the soil.”

Cover crops are no panacea, the experts said. Plants or seed mixtures commonly used in other parts of the country may falter or fail in California’s Mediterranean climate, with its variable amounts of winter-months rain.

And don’t expect immediate results, said Dennis Chessman, state agronomist for the Natural Resources Conservation Service.

“Cover crops (are) a long-term commitment,” he said.

It may be three to five years before the benefits become evident.

In the short term, like any plant, it takes water to produce a cover crop, Chessman said.

But over the long term, “It changes the soil, and what happens is we have a net gain in soil moisture.”

He said: “If we can store whatever rainfall we get in the soil for the next crop, that’s a benefit to us.”

That’s been the experience of Christopher Locke, who grows walnuts and cherries on land adjoining the Plant Materials Center and who attended the field day Tuesday.

After 20 years of using cover crops in his orchards, he believes they do require some additional water.

“But it’s worth it, I feel,” he said, citing the improvements to his soils, increased organic content and providing habitat for beneficial insects.

Chris Storm, viticulturalist for Vino Farms, which operates thousands of acres of vineyards in the northern Central Valley and North Coast, said he has tried a variety of cover crops over the past eight years or so.

Currently, on the ground between lines of trellised grapevines, he plants alternate rows of an annual seed mix — peas, beans, oats and tricale (a hybrid grain) — with perennial brome grasses. Then those rows are switched every three to six years.

One result he sees is more organic matter and increased moisture retention.

“If we can delay our irrigation by two weeks,” he said, “it’s huge.”

— Contact reporter Reed Fujii at (209) 546-8253 or rfujii@recordnet.com. Follow him on Twitter @ReedBiznews.

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